Fine-grained network controls that are coming with next-generation mobile technology could make some demanding mobile applications such as video perform better but may also raise Net neutrality concerns.

LTE (Long-Term Evolution), the fourth-generation mobile technology expected to be most widely adopted by carriers around the world, is designed to boost wireless data speeds and more efficiently serve subscribers. But along with that standard come others that define the IP network behind the cell towers. One of them, called PCRF (Packet Core Routing Function), will give carriers much more fine-grained control over how well applications and services perform.

PCRF has also been extended to 3G, and some vendors and carriers want to use the new technology to deal with growing demands on mobile data networks. On Thursday, Alcatel-Lucent extended its PCRF software, which was introduced last year, from LTE to 2.5G and 3G infrastructure. The company said Thursday that its 5780 Dynamic Services Controller, which can perform PCRF for both 3G and LTE networks, is in trials and will be available in the second half of this year. Alcatel is only the latest in a long line of vendors to offer PCRF software, which is part of a set of network management technologies called EPC (Evolved Packet Core).

EPC is very new technology -- it has generated no measurable revenue, according to market research firm Dell'Oro Group -- but all the drivers are in place for it to be widely deployed over the coming years, said Dell'Oro analyst Greg Collins. Demand for mobile data is growing fast, and carriers would like to control how the applications offered on their mobile networks perform. PCRF could have a major impact on carriers' businesses and subscribers' mobile experiences. Among other things, the technology could be used to give certain applications and users better performance than others. Carriers could even sell preferential treatment to application providers, where that practice is legal, vendors and analysts say.

But because the technology can define grades of service for both subscribers and content providers, it may run headlong into the growing debate in the U.S. over wireless Net neutrality. For example, the idea of selling priority to certain providers of over-the-top applications and services, even if that priority were offered to any providers that could pay, has drawn the ire of some Net neutrality advocates.

The need for tighter network management is growing out of the rapid increase in demand for mobile data services, the same trend that made LTE itself necessary. As more wireless subscribers try to use ever more bandwidth-intensive applications, carriers want mechanisms to ensure that the most important or sensitive uses of the network don't get trampled. EPC gives them tools to control, to some degree, the speed or QOS (quality of service) of individual applications.

"I can allocate QOS to a voice channel, or a data channel ... or a television service, for example," said William Guinn, chief technology officer of Amdocs, which makes back-end systems for carriers. "If you're downloading movies, for example, I might want to make sure you get [good] voice quality even if your downloads may take a couple of seconds longer."

Carriers could use PCRF in a variety of ways, according to Chetan Sharma, an independent mobile analyst. It defines nine levels of quality of service based on network delay and packet loss, four of which are guaranteed, he said. When the network is heavily loaded, users with a more expensive plan could get their Web pages and videos faster than those with lower-priced plans. In addition, the carrier could dial back performance for certain types of applications, no matter who was using them. And when subscribers reach the monthly download limit on a particular plan, their connection performance could be dialed back.

Software vendors are developing a variety of tools for controlling services based on policy. Bridgewater, a mobile network management vendor that already offers PCRF software for both LTE and 3G, says it can extend policy-based controls out to the radio access network. Later this year, Bridgewater plans to introduce software that can selectively offload cellular traffic onto faster networks where they are available, said Joanne Steinberg, Bridgewater's marketing director. Customers with higher-grade plans might find their data connections automatically shifting to Wi-Fi when the cellular network becomes congested, if the carrier considers that a benefit, she said.

Managing users' performance based on policies could allow carriers to smooth out the peaks in data demand, producing annual cost savings of more than 10% for U.S. operators by 2013, according to analyst Sharma.

As long as the terms of those "gold, silver and bronze" plans were clearly spelled out, it would be legal to offer them in most places, Sharma said. The main barrier would be consumer expectations in countries such as the U.S., where all-you-can-eat service has been the norm. For that reason, shoppers are likely to find separate classes of service in Europe first, he said.

Priority for over-the-top application providers could be a trickier proposition. Using PCRF, a carrier could put certain applications or services on a higher tier to ensure a smooth user experience even at busy times, Sharma said. For that assurance, carriers could charge a fee or a percentage of the application provider's revenue, Alcatel and other vendors acknowledged.

"I can negotiate with a carrier to get the type of service I'm looking for," said Amdocs' Guinn, giving the hypothetical example of a health-care company that gives patients medical monitors that send data over a mobile operator's network.

As long as the carrier didn't use the policy tools to give its own applications an edge over those of third parties, it wouldn't violate current Net neutrality rules in the U.S., which involve blocking or impeding a particular company's service, Guinn said.

However, to some critics, this idea raises the specter of carriers as gatekeepers on what should be an open marketplace of online applications.

"That has incredibly harmful impacts on competition and ... consumer choice ... and innovation," said Chris Riley, policy counsel for Free Press, a U.S. media reform group that has fought against blocking of certain applications by service providers. Also, if a carrier can charge for priority access to a congested network, it has less incentive to invest in a fatter pipe, he said. "They are managing scarcity and creating an environment of scarcity to sell this enhanced access."

The FCC's Net neutrality guidelines only cover wired networks today, but the agency is now considering stronger rules, including ones that would extend into the wireless world. The FCC is already proposing rules that would ban carriers from charging third-party service providers for better performance, Riley said.

"There's a good argument to be made that this kind of prioritization does basically disadvantage new entrants" to the mobile application world, said Fred von Lohmann, senior staff attorney at the Electronic Frontier Foundation. That argument and others about wireless Net neutrality will probably play out over the next three years or more, von Lohmann said. "We're not going to get a clear, final answer for some time," he said.